This invention is concerned with the structural improvement of tear-off convenience bottle caps formed out of lightweight sheet metal. The desirability of effecting further refinement in existing tear-off bottle caps becomes more self-evident as their general usage increases. This growth being due in part to recyclable or reusable glass containers as well as the constant consumer demand for convenience packaging. One aspect of known tear-off bottle caps where the need for further refinement has become particularly apparent concerns the easy removal of the cap from the underlying bottle lip or finish at the termination of the tearing action. Such removal, for optimum consumer acceptance, must be effected with minimal effort to avoid spillage and the mess attendant thereto resulting from the instability of the bottle and its attached cap caused by the applied pressure to remove the cap from the bottle. Variations in tearing pattern as determined by existing score line configurations have not, as yet completely fulfilled the above mentioned need in that the other basic structural requirements of the cap must still be met at the same time removal is being eased. Consequently, optimum positioning of the cap scoring must advantageously provide for adequate pressure retention as well as ease of tearing prior to cap removal and finally ease of cap removal from the bottle lip.
Another aspect of prior art tear-off bottle caps susceptible of further refinement concerns the degree of rigidity imparted to the cap in its fabrication so as to effectively withstand the rigors and abuse of in-process handling and shipment. This aspect has particular significance in cap constructions employing a radially extending gripping ear which not only required a substantial degree of stability for efficient high speed handling operations but must, in addition, possess sufficient stiffening to effectively aid the tearing action.